Allocate CheckCloudConnection object on stack

Fixes a memory leak: CheckCloudConnection was allocated on the heap,
but never deleted.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/checkcloudconnection.cpp

@@ -103,6 +103,5 @@ extern "C" bool canReachCloudServer()
 {
 	if (verbose)
 		qWarning() << "Cloud storage: checking connection to cloud server";
-	CheckCloudConnection *checker = new CheckCloudConnection;
-	return checker->checkServer();
+	return CheckCloudConnection().checkServer();
 }